includes/diff/DifferenceEngine.php

   1 <?php
   2 /**
   3  * User interface for the difference engine.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @ingroup DifferenceEngine
  22  */
  23
  24 /**
  25  * Constant to indicate diff cache compatibility.
  26  * Bump this when changing the diff formatting in a way that
  27  * fixes important bugs or such to force cached diff views to
  28  * clear.
  29  */
  30 define( 'MW_DIFF_VERSION', '1.11a' );
  31
  32 /**
  33  * @todo document
  34  * @ingroup DifferenceEngine
  35  */
  36 class DifferenceEngine extends ContextSource {
  37         /**#@+
  38          * @private
  39          */
  40         var $mOldid, $mNewid;
  41         var $mOldContent, $mNewContent;
  42         protected $mDiffLang;
  43
  44         /**
  45          * @var Title
  46          */
  47         var $mOldPage, $mNewPage;
  48         var $mRcidMarkPatrolled;
  49
  50         /**
  51          * @var Revision
  52          */
  53         var $mOldRev, $mNewRev;
  54         private $mRevisionsIdsLoaded = false; // Have the revisions IDs been loaded
  55         var $mRevisionsLoaded = false; // Have the revisions been loaded
  56         var $mTextLoaded = 0; // How many text blobs have been loaded, 0, 1 or 2?
  57         var $mCacheHit = false; // Was the diff fetched from cache?
  58
  59         /**
  60          * Set this to true to add debug info to the HTML output.
  61          * Warning: this may cause RSS readers to spuriously mark articles as "new"
  62          * (bug 20601)
  63          */
  64         var $enableDebugComment = false;
  65
  66         // If true, line X is not displayed when X is 1, for example to increase
  67         // readability and conserve space with many small diffs.
  68         protected $mReducedLineNumbers = false;
  69
  70         // Link to action=markpatrolled
  71         protected $mMarkPatrolledLink = null;
  72
  73         protected $unhide = false; # show rev_deleted content if allowed
  74         /**#@-*/
  75
  76         /**
  77          * Constructor
  78          * @param $context IContextSource context to use, anything else will be ignored
  79          * @param $old Integer old ID we want to show and diff with.
  80          * @param $new String either 'prev' or 'next'.
  81          * @param $rcid Integer ??? FIXME (default 0)
  82          * @param $refreshCache boolean If set, refreshes the diff cache
  83          * @param $unhide boolean If set, allow viewing deleted revs
  84          */
  85         function __construct( $context = null, $old = 0, $new = 0, $rcid = 0,
  86                 $refreshCache = false, $unhide = false )
  87         {
  88                 if ( $context instanceof IContextSource ) {
  89                         $this->setContext( $context );
  90                 }
  91
  92                 wfDebug( "DifferenceEngine old '$old' new '$new' rcid '$rcid'\n" );
  93
  94                 $this->mOldid = $old;
  95                 $this->mNewid = $new;
  96                 $this->mRcidMarkPatrolled = intval( $rcid );  # force it to be an integer
  97                 $this->mRefreshCache = $refreshCache;
  98                 $this->unhide = $unhide;
  99         }
 100
 101         /**
 102          * @param $value bool
 103          */
 104         function setReducedLineNumbers( $value = true ) {
 105                 $this->mReducedLineNumbers = $value;
 106         }
 107
 108         /**
 109          * @return Language
 110          */
 111         function getDiffLang() {
 112                 if ( $this->mDiffLang === null ) {
 113                         # Default language in which the diff text is written.
 114                         $this->mDiffLang = $this->getTitle()->getPageLanguage();
 115                 }
 116                 return $this->mDiffLang;
 117         }
 118
 119         /**
 120          * @return bool
 121          */
 122         function wasCacheHit() {
 123                 return $this->mCacheHit;
 124         }
 125
 126         /**
 127          * @return int
 128          */
 129         function getOldid() {
 130                 $this->loadRevisionIds();
 131                 return $this->mOldid;
 132         }
 133
 134         /**
 135          * @return Bool|int
 136          */
 137         function getNewid() {
 138                 $this->loadRevisionIds();
 139                 return $this->mNewid;
 140         }
 141
 142         /**
 143          * Look up a special:Undelete link to the given deleted revision id,
 144          * as a workaround for being unable to load deleted diffs in currently.
 145          *
 146          * @param int $id revision ID
 147          * @return mixed URL or false
 148          */
 149         function deletedLink( $id ) {
 150                 if ( $this->getUser()->isAllowed( 'deletedhistory' ) ) {
 151                         $dbr = wfGetDB( DB_SLAVE );
 152                         $row = $dbr->selectRow('archive', '*',
 153                                 array( 'ar_rev_id' => $id ),
 154                                 __METHOD__ );
 155                         if ( $row ) {
 156                                 $rev = Revision::newFromArchiveRow( $row );
 157                                 $title = Title::makeTitleSafe( $row->ar_namespace, $row->ar_title );
 158                                 return SpecialPage::getTitleFor( 'Undelete' )->getFullURL( array(
 159                                         'target' => $title->getPrefixedText(),
 160                                         'timestamp' => $rev->getTimestamp()
 161                                 ));
 162                         }
 163                 }
 164                 return false;
 165         }
 166
 167         /**
 168          * Build a wikitext link toward a deleted revision, if viewable.
 169          *
 170          * @param int $id revision ID
 171          * @return string wikitext fragment
 172          */
 173         function deletedIdMarker( $id ) {
 174                 $link = $this->deletedLink( $id );
 175                 if ( $link ) {
 176                         return "[$link $id]";
 177                 } else {
 178                         return $id;
 179                 }
 180         }
 181
 182         private function showMissingRevision() {
 183                 $out = $this->getOutput();
 184
 185                 $missing = array();
 186                 if ( $this->mOldRev === null ) {
 187                         $missing[] = $this->deletedIdMarker( $this->mOldid );
 188                 }
 189                 if ( $this->mNewRev === null ) {
 190                         $missing[] = $this->deletedIdMarker( $this->mNewid );
 191                 }
 192
 193                 $out->setPageTitle( $this->msg( 'errorpagetitle' ) );
 194                 $out->addWikiMsg( 'difference-missing-revision',
 195                         $this->getLanguage()->listToText( $missing ), count( $missing ) );
 196         }
 197
 198         function showDiffPage( $diffOnly = false ) {
 199                 wfProfileIn( __METHOD__ );
 200
 201                 # Allow frames except in certain special cases
 202                 $out = $this->getOutput();
 203                 $out->allowClickjacking();
 204                 $out->setRobotPolicy( 'noindex,nofollow' );
 205
 206                 if ( !$this->loadRevisionData() ) {
 207                         $this->showMissingRevision();
 208                         wfProfileOut( __METHOD__ );
 209                         return;
 210                 }
 211
 212                 $user = $this->getUser();
 213                 $permErrors = $this->mNewPage->getUserPermissionsErrors( 'read', $user );
 214                 if ( $this->mOldPage ) { # mOldPage might not be set, see below.
 215                         $permErrors = wfMergeErrorArrays( $permErrors,
 216                                 $this->mOldPage->getUserPermissionsErrors( 'read', $user ) );
 217                 }
 218                 if ( count( $permErrors ) ) {
 219                         wfProfileOut( __METHOD__ );
 220                         throw new PermissionsError( 'read', $permErrors );
 221                 }
 222
 223                 # If external diffs are enabled both globally and for the user,
 224                 # we'll use the application/x-external-editor interface to call
 225                 # an external diff tool like kompare, kdiff3, etc.
 226                 if ( ExternalEdit::useExternalEngine( $this->getContext(), 'diff' ) ) {
 227                         //TODO: come up with a good solution for non-text content here.
 228                         //      at least, the content format needs to be passed to the client somehow.
 229                         //      Currently, action=raw will just fail for non-text content.
 230
 231                         $urls = array(
 232                                 'File' => array( 'Extension' => 'wiki', 'URL' =>
 233                                         # This should be mOldPage, but it may not be set, see below.
 234                                         $this->mNewPage->getCanonicalURL( array(
 235                                                 'action' => 'raw', 'oldid' => $this->mOldid ) )
 236                                 ),
 237                                 'File2' => array( 'Extension' => 'wiki', 'URL' =>
 238                                         $this->mNewPage->getCanonicalURL( array(
 239                                                 'action' => 'raw', 'oldid' => $this->mNewid ) )
 240                                 ),
 241                         );
 242
 243                         $externalEditor = new ExternalEdit( $this->getContext(), $urls );
 244                         $externalEditor->execute();
 245
 246                         wfProfileOut( __METHOD__ );
 247                         return;
 248                 }
 249
 250                 $rollback = '';
 251                 $undoLink = '';
 252
 253                 $query = array();
 254                 # Carry over 'diffonly' param via navigation links
 255                 if ( $diffOnly != $user->getBoolOption( 'diffonly' ) ) {
 256                         $query['diffonly'] = $diffOnly;
 257                 }
 258                 # Cascade unhide param in links for easy deletion browsing
 259                 if ( $this->unhide ) {
 260                         $query['unhide'] = 1;
 261                 }
 262
 263                 # Check if one of the revisions is deleted/suppressed
 264                 $deleted = $suppressed = false;
 265                 $allowed = $this->mNewRev->userCan( Revision::DELETED_TEXT, $user );
 266
 267                 # mOldRev is false if the difference engine is called with a "vague" query for
 268                 # a diff between a version V and its previous version V' AND the version V
 269                 # is the first version of that article. In that case, V' does not exist.
 270                 if ( $this->mOldRev === false ) {
 271                         $out->setPageTitle( $this->msg( 'difference-title', $this->mNewPage->getPrefixedText() ) );
 272                         $samePage = true;
 273                         $oldHeader = '';
 274                 } else {
 275                         wfRunHooks( 'DiffViewHeader', array( $this, $this->mOldRev, $this->mNewRev ) );
 276
 277                         $sk = $this->getSkin();
 278                         if ( method_exists( $sk, 'suppressQuickbar' ) ) {
 279                                 $sk->suppressQuickbar();
 280                         }
 281
 282                         if ( $this->mNewPage->equals( $this->mOldPage ) ) {
 283                                 $out->setPageTitle( $this->msg( 'difference-title', $this->mNewPage->getPrefixedText() ) );
 284                                 $samePage = true;
 285                         } else {
 286                                 $out->setPageTitle( $this->msg( 'difference-title-multipage', $this->mOldPage->getPrefixedText(),
 287                                         $this->mNewPage->getPrefixedText() ) );
 288                                 $out->addSubtitle( $this->msg( 'difference-multipage' ) );
 289                                 $samePage = false;
 290                         }
 291
 292                         if ( $samePage && $this->mNewPage->quickUserCan( 'edit', $user ) ) {
 293                                 if ( $this->mNewRev->isCurrent() && $this->mNewPage->userCan( 'rollback', $user ) ) {
 294                                         $out->preventClickjacking();
 295                                         $rollback = '&#160;&#160;&#160;' . Linker::generateRollback( $this->mNewRev, $this->getContext() );
 296                                 }
 297                                 if ( !$this->mOldRev->isDeleted( Revision::DELETED_TEXT ) && !$this->mNewRev->isDeleted( Revision::DELETED_TEXT ) ) {
 298                                         $undoLink = ' ' . $this->msg( 'parentheses' )->rawParams(
 299                                                 Html::element( 'a', array(
 300                                                         'href' => $this->mNewPage->getLocalUrl( array(
 301                                                                 'action' => 'edit',
 302                                                                 'undoafter' => $this->mOldid,
 303                                                                 'undo' => $this->mNewid ) ),
 304                                                         'title' => Linker::titleAttrib( 'undo' )
 305                                                 ),
 306                                                 $this->msg( 'editundo' )->text()
 307                                         ) )->escaped();
 308                                 }
 309                         }
 310
 311                         # Make "previous revision link"
 312                         if ( $samePage && $this->mOldRev->getPrevious() ) {
 313                                 $prevlink = Linker::linkKnown(
 314                                         $this->mOldPage,
 315                                         $this->msg( 'previousdiff' )->escaped(),
 316                                         array( 'id' => 'differences-prevlink' ),
 317                                         array( 'diff' => 'prev', 'oldid' => $this->mOldid ) + $query
 318                                 );
 319                         } else {
 320                                 $prevlink = '&#160;';
 321                         }
 322
 323                         if ( $this->mOldRev->isMinor() ) {
 324                                 $oldminor = ChangesList::flag( 'minor' );
 325                         } else {
 326                                 $oldminor = '';
 327                         }
 328
 329                         $ldel = $this->revisionDeleteLink( $this->mOldRev );
 330                         $oldRevisionHeader = $this->getRevisionHeader( $this->mOldRev, 'complete' );
 331
 332                         $oldHeader = '<div id="mw-diff-otitle1"><strong>' . $oldRevisionHeader . '</strong></div>' .
 333                                 '<div id="mw-diff-otitle2">' .
 334                                         Linker::revUserTools( $this->mOldRev, !$this->unhide ) . '</div>' .
 335                                 '<div id="mw-diff-otitle3">' . $oldminor .
 336                                         Linker::revComment( $this->mOldRev, !$diffOnly, !$this->unhide ) . $ldel . '</div>' .
 337                                 '<div id="mw-diff-otitle4">' . $prevlink . '</div>';
 338
 339                         if ( $this->mOldRev->isDeleted( Revision::DELETED_TEXT ) ) {
 340                                 $deleted = true; // old revisions text is hidden
 341                                 if ( $this->mOldRev->isDeleted( Revision::DELETED_RESTRICTED ) ) {
 342                                         $suppressed = true; // also suppressed
 343                                 }
 344                         }
 345
 346                         # Check if this user can see the revisions
 347                         if ( !$this->mOldRev->userCan( Revision::DELETED_TEXT, $user ) ) {
 348                                 $allowed = false;
 349                         }
 350                 }
 351
 352                 # Make "next revision link"
 353                 # Skip next link on the top revision
 354                 if ( $samePage && !$this->mNewRev->isCurrent() ) {
 355                         $nextlink = Linker::linkKnown(
 356                                 $this->mNewPage,
 357                                 $this->msg( 'nextdiff' )->escaped(),
 358                                 array( 'id' => 'differences-nextlink' ),
 359                                 array( 'diff' => 'next', 'oldid' => $this->mNewid ) + $query
 360                         );
 361                 } else {
 362                         $nextlink = '&#160;';
 363                 }
 364
 365                 if ( $this->mNewRev->isMinor() ) {
 366                         $newminor = ChangesList::flag( 'minor' );
 367                 } else {
 368                         $newminor = '';
 369                 }
 370
 371                 # Handle RevisionDelete links...
 372                 $rdel = $this->revisionDeleteLink( $this->mNewRev );
 373                 $newRevisionHeader = $this->getRevisionHeader( $this->mNewRev, 'complete' ) . $undoLink;
 374
 375                 $newHeader = '<div id="mw-diff-ntitle1"><strong>' . $newRevisionHeader . '</strong></div>' .
 376                         '<div id="mw-diff-ntitle2">' . Linker::revUserTools( $this->mNewRev, !$this->unhide ) .
 377                                 " $rollback</div>" .
 378                         '<div id="mw-diff-ntitle3">' . $newminor .
 379                                 Linker::revComment( $this->mNewRev, !$diffOnly, !$this->unhide ) . $rdel . '</div>' .
 380                         '<div id="mw-diff-ntitle4">' . $nextlink . $this->markPatrolledLink() . '</div>';
 381
 382                 if ( $this->mNewRev->isDeleted( Revision::DELETED_TEXT ) ) {
 383                         $deleted = true; // new revisions text is hidden
 384                         if ( $this->mNewRev->isDeleted( Revision::DELETED_RESTRICTED ) )
 385                                 $suppressed = true; // also suppressed
 386                 }
 387
 388                 # If the diff cannot be shown due to a deleted revision, then output
 389                 # the diff header and links to unhide (if available)...
 390                 if ( $deleted && ( !$this->unhide || !$allowed ) ) {
 391                         $this->showDiffStyle();
 392                         $multi = $this->getMultiNotice();
 393                         $out->addHTML( $this->addHeader( '', $oldHeader, $newHeader, $multi ) );
 394                         if ( !$allowed ) {
 395                                 $msg = $suppressed ? 'rev-suppressed-no-diff' : 'rev-deleted-no-diff';
 396                                 # Give explanation for why revision is not visible
 397                                 $out->wrapWikiMsg( "<div id='mw-$msg' class='mw-warning plainlinks'>\n$1\n</div>\n",
 398                                         array( $msg ) );
 399                         } else {
 400                                 # Give explanation and add a link to view the diff...
 401                                 $link = $this->getTitle()->getFullUrl( $this->getRequest()->appendQueryValue( 'unhide', '1', true ) );
 402                                 $msg = $suppressed ? 'rev-suppressed-unhide-diff' : 'rev-deleted-unhide-diff';
 403                                 $out->wrapWikiMsg( "<div id='mw-$msg' class='mw-warning plainlinks'>\n$1\n</div>\n", array( $msg, $link ) );
 404                         }
 405                 # Otherwise, output a regular diff...
 406                 } else {
 407                         # Add deletion notice if the user is viewing deleted content
 408                         $notice = '';
 409                         if ( $deleted ) {
 410                                 $msg = $suppressed ? 'rev-suppressed-diff-view' : 'rev-deleted-diff-view';
 411                                 $notice = "<div id='mw-$msg' class='mw-warning plainlinks'>\n" . $this->msg( $msg )->parse() . "</div>\n";
 412                         }
 413                         $this->showDiff( $oldHeader, $newHeader, $notice );
 414                         if ( !$diffOnly ) {
 415                                 $this->renderNewRevision();
 416                         }
 417                 }
 418                 wfProfileOut( __METHOD__ );
 419         }
 420
 421         /**
 422          * Get a link to mark the change as patrolled, or '' if there's either no
 423          * revision to patrol or the user is not allowed to to it.
 424          * Side effect: this method will call OutputPage::preventClickjacking()
 425          * when a link is builded.
 426          *
 427          * @return String
 428          */
 429         protected function markPatrolledLink() {
 430                 global $wgUseRCPatrol;
 431
 432                 if ( $this->mMarkPatrolledLink === null ) {
 433                         // Prepare a change patrol link, if applicable
 434                         if ( $wgUseRCPatrol && $this->mNewPage->quickUserCan( 'patrol', $this->getUser() ) ) {
 435                                 // If we've been given an explicit change identifier, use it; saves time
 436                                 if ( $this->mRcidMarkPatrolled ) {
 437                                         $rcid = $this->mRcidMarkPatrolled;
 438                                         $rc = RecentChange::newFromId( $rcid );
 439                                         // Already patrolled?
 440                                         $rcid = is_object( $rc ) && !$rc->getAttribute( 'rc_patrolled' ) ? $rcid : 0;
 441                                 } else {
 442                                         // Look for an unpatrolled change corresponding to this diff
 443                                         $db = wfGetDB( DB_SLAVE );
 444                                         $change = RecentChange::newFromConds(
 445                                                 array(
 446                                                 // Redundant user,timestamp condition so we can use the existing index
 447                                                         'rc_user_text'  => $this->mNewRev->getRawUserText(),
 448                                                         'rc_timestamp'  => $db->timestamp( $this->mNewRev->getTimestamp() ),
 449                                                         'rc_this_oldid' => $this->mNewid,
 450                                                         'rc_last_oldid' => $this->mOldid,
 451                                                         'rc_patrolled'  => 0
 452                                                 ),
 453                                                 __METHOD__
 454                                         );
 455                                         if ( $change instanceof RecentChange ) {
 456                                                 $rcid = $change->mAttribs['rc_id'];
 457                                                 $this->mRcidMarkPatrolled = $rcid;
 458                                         } else {
 459                                                 // None found
 460                                                 $rcid = 0;
 461                                         }
 462                                 }
 463                                 // Build the link
 464                                 if ( $rcid ) {
 465                                         $this->getOutput()->preventClickjacking();
 466                                         $token = $this->getUser()->getEditToken( $rcid );
 467                                         $this->mMarkPatrolledLink = ' <span class="patrollink">[' . Linker::linkKnown(
 468                                                 $this->mNewPage,
 469                                                 $this->msg( 'markaspatrolleddiff' )->escaped(),
 470                                                 array(),
 471                                                 array(
 472                                                         'action' => 'markpatrolled',
 473                                                         'rcid' => $rcid,
 474                                                         'token' => $token,
 475                                                 )
 476                                         ) . ']</span>';
 477                                 } else {
 478                                         $this->mMarkPatrolledLink = '';
 479                                 }
 480                         } else {
 481                                 $this->mMarkPatrolledLink = '';
 482                         }
 483                 }
 484
 485                 return $this->mMarkPatrolledLink;
 486         }
 487
 488         /**
 489          * @param $rev Revision
 490          * @return String
 491          */
 492         protected function revisionDeleteLink( $rev ) {
 493                 $link = Linker::getRevDeleteLink( $this->getUser(), $rev, $rev->getTitle() );
 494                 if ( $link !== '' ) {
 495                         $link = '&#160;&#160;&#160;' . $link . ' ';
 496                 }
 497                 return $link;
 498         }
 499
 500         /**
 501          * Show the new revision of the page.
 502          */
 503         function renderNewRevision() {
 504                 wfProfileIn( __METHOD__ );
 505                 $out = $this->getOutput();
 506                 $revHeader = $this->getRevisionHeader( $this->mNewRev );
 507                 # Add "current version as of X" title
 508                 $out->addHTML( "<hr class='diff-hr' />
 509                 <h2 class='diff-currentversion-title'>{$revHeader}</h2>\n" );
 510                 # Page content may be handled by a hooked call instead...
 511                 if ( wfRunHooks( 'ArticleContentOnDiff', array( $this, $out ) ) ) {
 512                         $this->loadNewText();
 513                         $out->setRevisionId( $this->mNewid );
 514                         $out->setRevisionTimestamp( $this->mNewRev->getTimestamp() );
 515                         $out->setArticleFlag( true );
 516
 517                         // NOTE: only needed for B/C: custom rendering of JS/CSS via hook
 518                         if ( $this->mNewPage->isCssJsSubpage() || $this->mNewPage->isCssOrJsPage() ) {
 519                                 // Stolen from Article::view --AG 2007-10-11
 520                                 // Give hooks a chance to customise the output
 521                                 // @TODO: standardize this crap into one function
 522                                 if ( ContentHandler::runLegacyHooks( 'ShowRawCssJs', array( $this->mNewContent, $this->mNewPage, $out ) ) ) {
 523                                         // NOTE: deprecated hook, B/C only
 524                                         // use the content object's own rendering
 525                                         $cnt = $this->mNewRev->getContent();
 526                                         $po = $cnt ? $cnt->getParserOutput( $this->mNewRev->getTitle(), $this->mNewRev->getId() ) : null;
 527                                         $txt = $po ? $po->getText() : '';
 528                                         $out->addHTML( $txt );
 529                                 }
 530                         } elseif( !wfRunHooks( 'ArticleContentViewCustom', array( $this->mNewContent, $this->mNewPage, $out ) ) ) {
 531                                 // Handled by extension
 532                         } elseif( !ContentHandler::runLegacyHooks( 'ArticleViewCustom', array( $this->mNewContent, $this->mNewPage, $out ) ) ) {
 533                                 // NOTE: deprecated hook, B/C only
 534                                 // Handled by extension
 535                         } else {
 536                                 // Normal page
 537                                 if ( $this->getTitle()->equals( $this->mNewPage ) ) {
 538                                         // If the Title stored in the context is the same as the one
 539                                         // of the new revision, we can use its associated WikiPage
 540                                         // object.
 541                                         $wikiPage = $this->getWikiPage();
 542                                 } else {
 543                                         // Otherwise we need to create our own WikiPage object
 544                                         $wikiPage = WikiPage::factory( $this->mNewPage );
 545                                 }
 546
 547                                 $parserOutput = $this->getParserOutput( $wikiPage, $this->mNewRev );
 548
 549                                 # Also try to load it as a redirect
 550                                 $rt = $this->mNewContent ? $this->mNewContent->getRedirectTarget() : null;
 551
 552                                 if ( $rt ) {
 553                                         $article = Article::newFromTitle( $this->mNewPage, $this->getContext() );
 554                                         $out->addHTML( $article->viewRedirect( $rt ) );
 555
 556                                         # WikiPage::getParserOutput() should not return false, but just in case
 557                                         if ( $parserOutput ) {
 558                                                 # Show categories etc.
 559                                                 $out->addParserOutputNoText( $parserOutput );
 560                                         }
 561                                 } else if ( $parserOutput ) {
 562                                         $out->addParserOutput( $parserOutput );
 563                                 }
 564                         }
 565                 }
 566                 # Add redundant patrol link on bottom...
 567                 $out->addHTML( $this->markPatrolledLink() );
 568
 569                 wfProfileOut( __METHOD__ );
 570         }
 571
 572         protected function getParserOutput( WikiPage $page, Revision $rev ) {
 573                 $parserOptions = $page->makeParserOptions( $this->getContext() );
 574
 575                 if ( !$rev->isCurrent() || !$rev->getTitle()->quickUserCan( "edit" ) ) {
 576                         $parserOptions->setEditSection( false );
 577                 }
 578
 579                 $parserOutput = $page->getParserOutput( $parserOptions, $rev->getId() );
 580                 return $parserOutput;
 581         }
 582
 583         /**
 584          * Get the diff text, send it to the OutputPage object
 585          * Returns false if the diff could not be generated, otherwise returns true
 586          *
 587          * @return bool
 588          */
 589         function showDiff( $otitle, $ntitle, $notice = '' ) {
 590                 $diff = $this->getDiff( $otitle, $ntitle, $notice );
 591                 if ( $diff === false ) {
 592                         $this->showMissingRevision();
 593                         return false;
 594                 } else {
 595                         $this->showDiffStyle();
 596                         $this->getOutput()->addHTML( $diff );
 597                         return true;
 598                 }
 599         }
 600
 601         /**
 602          * Add style sheets and supporting JS for diff display.
 603          */
 604         function showDiffStyle() {
 605                 $this->getOutput()->addModuleStyles( 'mediawiki.action.history.diff' );
 606         }
 607
 608         /**
 609          * Get complete diff table, including header
 610          *
 611          * @param $otitle Title: old title
 612          * @param $ntitle Title: new title
 613          * @param $notice String: HTML between diff header and body
 614          * @return mixed
 615          */
 616         function getDiff( $otitle, $ntitle, $notice = '' ) {
 617                 $body = $this->getDiffBody();
 618                 if ( $body === false ) {
 619                         return false;
 620                 } else {
 621                         $multi = $this->getMultiNotice();
 622                         return $this->addHeader( $body, $otitle, $ntitle, $multi, $notice );
 623                 }
 624         }
 625
 626         /**
 627          * Get the diff table body, without header
 628          *
 629          * @return mixed (string/false)
 630          */
 631         public function getDiffBody() {
 632                 global $wgMemc;
 633                 wfProfileIn( __METHOD__ );
 634                 $this->mCacheHit = true;
 635                 // Check if the diff should be hidden from this user
 636                 if ( !$this->loadRevisionData() ) {
 637                         wfProfileOut( __METHOD__ );
 638                         return false;
 639                 } elseif ( $this->mOldRev && !$this->mOldRev->userCan( Revision::DELETED_TEXT, $this->getUser() ) ) {
 640                         wfProfileOut( __METHOD__ );
 641                         return false;
 642                 } elseif ( $this->mNewRev && !$this->mNewRev->userCan( Revision::DELETED_TEXT, $this->getUser() ) ) {
 643                         wfProfileOut( __METHOD__ );
 644                         return false;
 645                 }
 646                 // Short-circuit
 647                 // If mOldRev is false, it means that the
 648                 if ( $this->mOldRev === false || ( $this->mOldRev && $this->mNewRev
 649                         && $this->mOldRev->getID() == $this->mNewRev->getID() ) )
 650                 {
 651                         wfProfileOut( __METHOD__ );
 652                         return '';
 653                 }
 654                 // Cacheable?
 655                 $key = false;
 656                 if ( $this->mOldid && $this->mNewid ) {
 657                         $key = wfMemcKey( 'diff', 'version', MW_DIFF_VERSION,
 658                                 'oldid', $this->mOldid, 'newid', $this->mNewid );
 659                         // Try cache
 660                         if ( !$this->mRefreshCache ) {
 661                                 $difftext = $wgMemc->get( $key );
 662                                 if ( $difftext ) {
 663                                         wfIncrStats( 'diff_cache_hit' );
 664                                         $difftext = $this->localiseLineNumbers( $difftext );
 665                                         $difftext .= "\n<!-- diff cache key $key -->\n";
 666                                         wfProfileOut( __METHOD__ );
 667                                         return $difftext;
 668                                 }
 669                         } // don't try to load but save the result
 670                 }
 671                 $this->mCacheHit = false;
 672
 673                 // Loadtext is permission safe, this just clears out the diff
 674                 if ( !$this->loadText() ) {
 675                         wfProfileOut( __METHOD__ );
 676                         return false;
 677                 }
 678
 679                 $difftext = $this->generateContentDiffBody( $this->mOldContent, $this->mNewContent );
 680
 681                 // Save to cache for 7 days
 682                 if ( !wfRunHooks( 'AbortDiffCache', array( &$this ) ) ) {
 683                         wfIncrStats( 'diff_uncacheable' );
 684                 } elseif ( $key !== false && $difftext !== false ) {
 685                         wfIncrStats( 'diff_cache_miss' );
 686                         $wgMemc->set( $key, $difftext, 7 * 86400 );
 687                 } else {
 688                         wfIncrStats( 'diff_uncacheable' );
 689                 }
 690                 // Replace line numbers with the text in the user's language
 691                 if ( $difftext !== false ) {
 692                         $difftext = $this->localiseLineNumbers( $difftext );
 693                 }
 694                 wfProfileOut( __METHOD__ );
 695                 return $difftext;
 696         }
 697
 698         /**
 699          * Make sure the proper modules are loaded before we try to
 700          * make the diff
 701          */
 702         private function initDiffEngines() {
 703                 global $wgExternalDiffEngine;
 704                 if ( $wgExternalDiffEngine == 'wikidiff' && !function_exists( 'wikidiff_do_diff' ) ) {
 705                         wfProfileIn( __METHOD__ . '-php_wikidiff.so' );
 706                         wfDl( 'php_wikidiff' );
 707                         wfProfileOut( __METHOD__ . '-php_wikidiff.so' );
 708                 }
 709                 elseif ( $wgExternalDiffEngine == 'wikidiff2' && !function_exists( 'wikidiff2_do_diff' ) ) {
 710                         wfProfileIn( __METHOD__ . '-php_wikidiff2.so' );
 711                         wfDl( 'wikidiff2' );
 712                         wfProfileOut( __METHOD__ . '-php_wikidiff2.so' );
 713                 }
 714         }
 715
 716         /**
 717          * Generate a diff, no caching.
 718          *
 719          * This implementation uses generateTextDiffBody() to generate a diff based on the default
 720          * serialization of the given Content objects. This will fail if $old or $new are not
 721          * instances of TextContent.
 722          *
 723          * Subclasses may override this to provide a different rendering for the diff,
 724          * perhaps taking advantage of the content's native form. This is required for all content
 725          * models that are not text based.
 726          *
 727          * @param $old Content: old content
 728          * @param $new Content: new content
 729          *
 730          * @since 1.21
 731          * @throws MWException if $old or $new are not instances of TextContent.
 732          */
 733         function generateContentDiffBody( Content $old, Content $new ) {
 734                 if ( !( $old instanceof TextContent ) ) {
 735                         throw new MWException( "Diff not implemented for " . get_class( $old ) . "; "
 736                                         . "override generateContentDiffBody to fix this." );
 737                 }
 738
 739                 if ( !( $new instanceof TextContent ) ) {
 740                         throw new MWException( "Diff not implemented for " . get_class( $new ) . "; "
 741                                 . "override generateContentDiffBody to fix this." );
 742                 }
 743
 744                 $otext = $old->serialize();
 745                 $ntext = $new->serialize();
 746
 747                 return $this->generateTextDiffBody( $otext, $ntext );
 748         }
 749
 750         /**
 751          * Generate a diff, no caching
 752          *
 753          * @param $otext String: old text, must be already segmented
 754          * @param $ntext String: new text, must be already segmented
 755          * @deprecated since 1.21, use generateContentDiffBody() instead!
 756          */
 757         function generateDiffBody( $otext, $ntext ) {
 758                 ContentHandler::deprecated( __METHOD__, "1.21" );
 759
 760                 return $this->generateTextDiffBody( $otext, $ntext );
 761         }
 762
 763         /**
 764          * Generate a diff, no caching
 765          *
 766          * @todo move this to TextDifferenceEngine, make DifferenceEngine abstract. At some point.
 767          *
 768          * @param $otext String: old text, must be already segmented
 769          * @param $ntext String: new text, must be already segmented
 770          * @return bool|string
 771          */
 772         function generateTextDiffBody( $otext, $ntext ) {
 773                 global $wgExternalDiffEngine, $wgContLang;
 774
 775                 wfProfileIn( __METHOD__ );
 776
 777                 $otext = str_replace( "\r\n", "\n", $otext );
 778                 $ntext = str_replace( "\r\n", "\n", $ntext );
 779
 780                 $this->initDiffEngines();
 781
 782                 if ( $wgExternalDiffEngine == 'wikidiff' && function_exists( 'wikidiff_do_diff' ) ) {
 783                         # For historical reasons, external diff engine expects
 784                         # input text to be HTML-escaped already
 785                         $otext = htmlspecialchars ( $wgContLang->segmentForDiff( $otext ) );
 786                         $ntext = htmlspecialchars ( $wgContLang->segmentForDiff( $ntext ) );
 787                         wfProfileOut( __METHOD__ );
 788                         return $wgContLang->unsegmentForDiff( wikidiff_do_diff( $otext, $ntext, 2 ) ) .
 789                         $this->debug( 'wikidiff1' );
 790                 }
 791
 792                 if ( $wgExternalDiffEngine == 'wikidiff2' && function_exists( 'wikidiff2_do_diff' ) ) {
 793                         # Better external diff engine, the 2 may some day be dropped
 794                         # This one does the escaping and segmenting itself
 795                         wfProfileIn( 'wikidiff2_do_diff' );
 796                         $text = wikidiff2_do_diff( $otext, $ntext, 2 );
 797                         $text .= $this->debug( 'wikidiff2' );
 798                         wfProfileOut( 'wikidiff2_do_diff' );
 799                         wfProfileOut( __METHOD__ );
 800                         return $text;
 801                 }
 802                 if ( $wgExternalDiffEngine != 'wikidiff3' && $wgExternalDiffEngine !== false ) {
 803                         # Diff via the shell
 804                         $tmpDir = wfTempDir();
 805                         $tempName1 = tempnam( $tmpDir, 'diff_' );
 806                         $tempName2 = tempnam( $tmpDir, 'diff_' );
 807
 808                         $tempFile1 = fopen( $tempName1, "w" );
 809                         if ( !$tempFile1 ) {
 810                                 wfProfileOut( __METHOD__ );
 811                                 return false;
 812                         }
 813                         $tempFile2 = fopen( $tempName2, "w" );
 814                         if ( !$tempFile2 ) {
 815                                 wfProfileOut( __METHOD__ );
 816                                 return false;
 817                         }
 818                         fwrite( $tempFile1, $otext );
 819                         fwrite( $tempFile2, $ntext );
 820                         fclose( $tempFile1 );
 821                         fclose( $tempFile2 );
 822                         $cmd = wfEscapeShellArg( $wgExternalDiffEngine, $tempName1, $tempName2 );
 823                         wfProfileIn( __METHOD__ . "-shellexec" );
 824                         $difftext = wfShellExec( $cmd );
 825                         $difftext .= $this->debug( "external $wgExternalDiffEngine" );
 826                         wfProfileOut( __METHOD__ . "-shellexec" );
 827                         unlink( $tempName1 );
 828                         unlink( $tempName2 );
 829                         wfProfileOut( __METHOD__ );
 830                         return $difftext;
 831                 }
 832
 833                 # Native PHP diff
 834                 $ota = explode( "\n", $wgContLang->segmentForDiff( $otext ) );
 835                 $nta = explode( "\n", $wgContLang->segmentForDiff( $ntext ) );
 836                 $diffs = new Diff( $ota, $nta );
 837                 $formatter = new TableDiffFormatter();
 838                 $difftext = $wgContLang->unsegmentForDiff( $formatter->format( $diffs ) ) .
 839                 wfProfileOut( __METHOD__ );
 840                 return $difftext;
 841         }
 842
 843         /**
 844          * Generate a debug comment indicating diff generating time,
 845          * server node, and generator backend.
 846          * @return string
 847          */
 848         protected function debug( $generator = "internal" ) {
 849                 global $wgShowHostnames;
 850                 if ( !$this->enableDebugComment ) {
 851                         return '';
 852                 }
 853                 $data = array( $generator );
 854                 if ( $wgShowHostnames ) {
 855                         $data[] = wfHostname();
 856                 }
 857                 $data[] = wfTimestamp( TS_DB );
 858                 return "<!-- diff generator: " .
 859                 implode( " ",
 860                 array_map(
 861                                         "htmlspecialchars",
 862                 $data ) ) .
 863                         " -->\n";
 864         }
 865
 866         /**
 867          * Replace line numbers with the text in the user's language
 868          * @return mixed
 869          */
 870         function localiseLineNumbers( $text ) {
 871                 return preg_replace_callback( '/<!--LINE (\d+)-->/',
 872                 array( &$this, 'localiseLineNumbersCb' ), $text );
 873         }
 874
 875         function localiseLineNumbersCb( $matches ) {
 876                 if ( $matches[1] === '1' && $this->mReducedLineNumbers ) return '';
 877                 return $this->msg( 'lineno' )->numParams( $matches[1] )->escaped();
 878         }
 879
 880
 881         /**
 882          * If there are revisions between the ones being compared, return a note saying so.
 883          * @return string
 884          */
 885         function getMultiNotice() {
 886                 if ( !is_object( $this->mOldRev ) || !is_object( $this->mNewRev ) ) {
 887                         return '';
 888                 } elseif ( !$this->mOldPage->equals( $this->mNewPage ) ) {
 889                         // Comparing two different pages? Count would be meaningless.
 890                         return '';
 891                 }
 892
 893                 if ( $this->mOldRev->getTimestamp() > $this->mNewRev->getTimestamp() ) {
 894                         $oldRev = $this->mNewRev; // flip
 895                         $newRev = $this->mOldRev; // flip
 896                 } else { // normal case
 897                         $oldRev = $this->mOldRev;
 898                         $newRev = $this->mNewRev;
 899                 }
 900
 901                 $nEdits = $this->mNewPage->countRevisionsBetween( $oldRev, $newRev );
 902                 if ( $nEdits > 0 ) {
 903                         $limit = 100; // use diff-multi-manyusers if too many users
 904                         $numUsers = $this->mNewPage->countAuthorsBetween( $oldRev, $newRev, $limit );
 905                         return self::intermediateEditsMsg( $nEdits, $numUsers, $limit );
 906                 }
 907                 return ''; // nothing
 908         }
 909
 910         /**
 911          * Get a notice about how many intermediate edits and users there are
 912          * @param $numEdits int
 913          * @param $numUsers int
 914          * @param $limit int
 915          * @return string
 916          */
 917         public static function intermediateEditsMsg( $numEdits, $numUsers, $limit ) {
 918                 if ( $numUsers > $limit ) {
 919                         $msg = 'diff-multi-manyusers';
 920                         $numUsers = $limit;
 921                 } else {
 922                         $msg = 'diff-multi';
 923                 }
 924                 return wfMessage( $msg )->numParams( $numEdits, $numUsers )->parse();
 925         }
 926
 927         /**
 928          * Get a header for a specified revision.
 929          *
 930          * @param $rev Revision
 931          * @param $complete String: 'complete' to get the header wrapped depending
 932          *        the visibility of the revision and a link to edit the page.
 933          * @return String HTML fragment
 934          */
 935         protected function getRevisionHeader( Revision $rev, $complete = '' ) {
 936                 $lang = $this->getLanguage();
 937                 $user = $this->getUser();
 938                 $revtimestamp = $rev->getTimestamp();
 939                 $timestamp = $lang->userTimeAndDate( $revtimestamp, $user );
 940                 $dateofrev = $lang->userDate( $revtimestamp, $user );
 941                 $timeofrev = $lang->userTime( $revtimestamp, $user );
 942
 943                 $header = $this->msg(
 944                         $rev->isCurrent() ? 'currentrev-asof' : 'revisionasof',
 945                         $timestamp,
 946                         $dateofrev,
 947                         $timeofrev
 948                 )->escaped();
 949
 950                 if ( $complete !== 'complete' ) {
 951                         return $header;
 952                 }
 953
 954                 $title = $rev->getTitle();
 955
 956                 $header = Linker::linkKnown( $title, $header, array(),
 957                         array( 'oldid' => $rev->getID() ) );
 958
 959                 if ( $rev->userCan( Revision::DELETED_TEXT, $user ) ) {
 960                         $editQuery = array( 'action' => 'edit' );
 961                         if ( !$rev->isCurrent() ) {
 962                                 $editQuery['oldid'] = $rev->getID();
 963                         }
 964
 965                         $msg = $this->msg( $title->quickUserCan( 'edit', $user ) ? 'editold' : 'viewsourceold' )->escaped();
 966                         $header .= ' ' . $this->msg( 'parentheses' )->rawParams(
 967                                 Linker::linkKnown( $title, $msg, array(), $editQuery ) )->plain();
 968                         if ( $rev->isDeleted( Revision::DELETED_TEXT ) ) {
 969                                 $header = Html::rawElement( 'span', array( 'class' => 'history-deleted' ), $header );
 970                         }
 971                 } else {
 972                         $header = Html::rawElement( 'span', array( 'class' => 'history-deleted' ), $header );
 973                 }
 974
 975                 return $header;
 976         }
 977
 978         /**
 979          * Add the header to a diff body
 980          *
 981          * @return string
 982          */
 983         function addHeader( $diff, $otitle, $ntitle, $multi = '', $notice = '' ) {
 984                 // shared.css sets diff in interface language/dir, but the actual content
 985                 // is often in a different language, mostly the page content language/dir
 986                 $tableClass = 'diff diff-contentalign-' . htmlspecialchars( $this->getDiffLang()->alignStart() );
 987                 $header = "<table class='$tableClass'>";
 988
 989                 if ( !$diff && !$otitle ) {
 990                         $header .= "
 991                         <tr style='vertical-align: top;'>
 992                         <td class='diff-ntitle'>{$ntitle}</td>
 993                         </tr>";
 994                         $multiColspan = 1;
 995                 } else {
 996                         if ( $diff ) { // Safari/Chrome show broken output if cols not used
 997                                 $header .= "
 998                                 <col class='diff-marker' />
 999                                 <col class='diff-content' />
1000                                 <col class='diff-marker' />
1001                                 <col class='diff-content' />";
1002                                 $colspan = 2;
1003                                 $multiColspan = 4;
1004                         } else {
1005                                 $colspan = 1;
1006                                 $multiColspan = 2;
1007                         }
1008                         $header .= "
1009                         <tr style='vertical-align: top;'>
1010                         <td colspan='$colspan' class='diff-otitle'>{$otitle}</td>
1011                         <td colspan='$colspan' class='diff-ntitle'>{$ntitle}</td>
1012                         </tr>";
1013                 }
1014
1015                 if ( $multi != '' ) {
1016                         $header .= "<tr><td colspan='{$multiColspan}' style='text-align: center;' class='diff-multi'>{$multi}</td></tr>";
1017                 }
1018                 if ( $notice != '' ) {
1019                         $header .= "<tr><td colspan='{$multiColspan}' style='text-align: center;'>{$notice}</td></tr>";
1020                 }
1021
1022                 return $header . $diff . "</table>";
1023         }
1024
1025         /**
1026          * Use specified text instead of loading from the database
1027          * @deprecated since 1.21, use setContent() instead.
1028          */
1029         function setText( $oldText, $newText ) {
1030                 ContentHandler::deprecated( __METHOD__, "1.21" );
1031
1032                 $oldContent = ContentHandler::makeContent( $oldText, $this->getTitle() );
1033                 $newContent = ContentHandler::makeContent( $newText, $this->getTitle() );
1034
1035                 $this->setContent( $oldContent, $newContent );
1036         }
1037
1038         /**
1039          * Use specified text instead of loading from the database
1040          * @since 1.21
1041          */
1042         function setContent( Content $oldContent, Content $newContent ) {
1043                 $this->mOldContent = $oldContent;
1044                 $this->mNewContent = $newContent;
1045
1046                 $this->mTextLoaded = 2;
1047                 $this->mRevisionsLoaded = true;
1048         }
1049
1050         /**
1051          * Set the language in which the diff text is written
1052          * (Defaults to page content language).
1053          * @since 1.19
1054          */
1055         function setTextLanguage( $lang ) {
1056                 $this->mDiffLang = wfGetLangObj( $lang );
1057         }
1058
1059         /**
1060          * Load revision IDs
1061          */
1062         private function loadRevisionIds() {
1063                 if ( $this->mRevisionsIdsLoaded ) {
1064                         return;
1065                 }
1066
1067                 $this->mRevisionsIdsLoaded = true;
1068
1069                 $old = $this->mOldid;
1070                 $new = $this->mNewid;
1071
1072                 if ( $new === 'prev' ) {
1073                         # Show diff between revision $old and the previous one.
1074                         # Get previous one from DB.
1075                         $this->mNewid = intval( $old );
1076                         $this->mOldid = $this->getTitle()->getPreviousRevisionID( $this->mNewid );
1077                 } elseif ( $new === 'next' ) {
1078                         # Show diff between revision $old and the next one.
1079                         # Get next one from DB.
1080                         $this->mOldid = intval( $old );
1081                         $this->mNewid = $this->getTitle()->getNextRevisionID( $this->mOldid );
1082                         if ( $this->mNewid === false ) {
1083                                 # if no result, NewId points to the newest old revision. The only newer
1084                                 # revision is cur, which is "0".
1085                                 $this->mNewid = 0;
1086                         }
1087                 } else {
1088                         $this->mOldid = intval( $old );
1089                         $this->mNewid = intval( $new );
1090                         wfRunHooks( 'NewDifferenceEngine', array( $this->getTitle(), &$this->mOldid, &$this->mNewid, $old, $new ) );
1091                 }
1092         }
1093
1094         /**
1095          * Load revision metadata for the specified articles. If newid is 0, then compare
1096          * the old article in oldid to the current article; if oldid is 0, then
1097          * compare the current article to the immediately previous one (ignoring the
1098          * value of newid).
1099          *
1100          * If oldid is false, leave the corresponding revision object set
1101          * to false. This is impossible via ordinary user input, and is provided for
1102          * API convenience.
1103          *
1104          * @return bool
1105          */
1106         function loadRevisionData() {
1107                 if ( $this->mRevisionsLoaded ) {
1108                         return true;
1109                 }
1110
1111                 // Whether it succeeds or fails, we don't want to try again
1112                 $this->mRevisionsLoaded = true;
1113
1114                 $this->loadRevisionIds();
1115
1116                 // Load the new revision object
1117                 $this->mNewRev = $this->mNewid
1118                         ? Revision::newFromId( $this->mNewid )
1119                         : Revision::newFromTitle( $this->getTitle(), false, Revision::READ_NORMAL );
1120
1121                 if ( !$this->mNewRev instanceof Revision ) {
1122                         return false;
1123                 }
1124
1125                 // Update the new revision ID in case it was 0 (makes life easier doing UI stuff)
1126                 $this->mNewid = $this->mNewRev->getId();
1127                 $this->mNewPage = $this->mNewRev->getTitle();
1128
1129                 // Load the old revision object
1130                 $this->mOldRev = false;
1131                 if ( $this->mOldid ) {
1132                         $this->mOldRev = Revision::newFromId( $this->mOldid );
1133                 } elseif ( $this->mOldid === 0 ) {
1134                         $rev = $this->mNewRev->getPrevious();
1135                         if ( $rev ) {
1136                                 $this->mOldid = $rev->getId();
1137                                 $this->mOldRev = $rev;
1138                         } else {
1139                                 // No previous revision; mark to show as first-version only.
1140                                 $this->mOldid = false;
1141                                 $this->mOldRev = false;
1142                         }
1143                 } /* elseif ( $this->mOldid === false ) leave mOldRev false; */
1144
1145                 if ( is_null( $this->mOldRev ) ) {
1146                         return false;
1147                 }
1148
1149                 if ( $this->mOldRev ) {
1150                         $this->mOldPage = $this->mOldRev->getTitle();
1151                 }
1152
1153                 return true;
1154         }
1155
1156         /**
1157          * Load the text of the revisions, as well as revision data.
1158          *
1159          * @return bool
1160          */
1161         function loadText() {
1162                 if ( $this->mTextLoaded == 2 ) {
1163                         return true;
1164                 } else {
1165                         // Whether it succeeds or fails, we don't want to try again
1166                         $this->mTextLoaded = 2;
1167                 }
1168
1169                 if ( !$this->loadRevisionData() ) {
1170                         return false;
1171                 }
1172                 if ( $this->mOldRev ) {
1173                         $this->mOldContent = $this->mOldRev->getContent( Revision::FOR_THIS_USER, $this->getUser() );
1174                         if ( $this->mOldContent === null ) {
1175                                 return false;
1176                         }
1177                 }
1178                 if ( $this->mNewRev ) {
1179                         $this->mNewContent = $this->mNewRev->getContent( Revision::FOR_THIS_USER, $this->getUser() );
1180                         if ( $this->mNewContent === null ) {
1181                                 return false;
1182                         }
1183                 }
1184                 return true;
1185         }
1186
1187         /**
1188          * Load the text of the new revision, not the old one
1189          *
1190          * @return bool
1191          */
1192         function loadNewText() {
1193                 if ( $this->mTextLoaded >= 1 ) {
1194                         return true;
1195                 } else {
1196                         $this->mTextLoaded = 1;
1197                 }
1198                 if ( !$this->loadRevisionData() ) {
1199                         return false;
1200                 }
1201                 $this->mNewContent = $this->mNewRev->getContent( Revision::FOR_THIS_USER, $this->getUser() );
1202                 return true;
1203         }
1204 }